index.js

const maxstacheStream = require('maxstache-stream')
const maxstache = require('maxstache')
const parallel = require('run-parallel')
const eos = require('end-of-stream')
const readdirp = require('readdirp')
const assert = require('assert')
const mkdirp = require('mkdirp')
const noop = require('noop2')
const path = require('path')
const pump = require('pump')
const fs = require('graceful-fs')

module.exports = copyTemplateDir

// High throughput template dir writes
// (str, str, obj, fn) -> null
function copyTemplateDir (srcDir, outDir, vars, cb) {
  if (!cb) {
    if (!vars) vars = noop
    cb = vars
    vars = {}
  }

  assert.strictEqual(typeof srcDir, 'string')
  assert.strictEqual(typeof outDir, 'string')
  assert.strictEqual(typeof vars, 'object')
  assert.strictEqual(typeof cb, 'function')

  // create directory
  mkdirp(outDir, function (err) {
    if (err) return cb(err)
    const rs = readdirp(srcDir, {})
    const streams = []
    const createdFiles = []

    // create a new stream for every file emitted
    rs.on('data', function (file) {
      createdFiles.push(path.join(outDir, maxstache(removeUnderscore(file.path), vars)))
      streams.push(writeFile(outDir, vars, file))
    })

    // delegate errors & close streams
    eos(rs, function (err) {
      if (err) return cb(err)
      parallel(streams, function (err) {
        if (err) return cb(err)
        cb(null, createdFiles)
      })
    })
  })
}

// write a file to a directory
// str -> stream
function writeFile (outDir, vars, file) {
  return function (done) {
    const fileName = file.path
    const inFile = file.fullPath
    const parentDir = path.basename(file.dirent.path)
    const outFile = path.join(outDir, maxstache(removeUnderscore(fileName), vars))
    
    mkdirp(path.join(outDir, maxstache(parentDir, vars)), function (err) {
      if (err) return done(err)

      const rs = fs.createReadStream(inFile)
      const ts = maxstacheStream(vars)
      const ws = fs.createWriteStream(outFile)

      pump(rs, ts, ws, done)
    })
  }
}

// remove a leading underscore
// str -> str
function removeUnderscore (filepath) {
  const parts = filepath.split(path.sep)
  const filename = parts.pop().replace(/^_/, '')
  return parts.concat([filename]).join(path.sep)
}